Frequently Asked Questions
Frequently Asked Questions related to 7-Zip as well as other topics related to the site.
Can 7-Zip be used in commercial organizations?
Yes, you can use 7-Zip in commercial organizations as it is free software. You don't have to spend anything for employing it. You don't even have to register, you can solely use it on any computer.
What makes the new version of 7-Zip create larger archives than the older version of 7- Zip?
The Newer versions of 7-Zip from version 15.06 utilize another file grouping rule by default for solid 7z archives. But the before 15.06 versions 7-Zip, utilized file grouping and sorting "by type" in other words by their extension.
The Newer version of 7-Zip favors two grouping orders:
- Sorting by name - as a default order.
- Sorting by type - if 'qs' is specified in the Parameters area in the "Add to archive" window. You will see that the compression ratio for various sorting procedures shows a large disparity if the dictionary size is not larger than the sizes of all files present. In the case of similar files in different folders, the sorting "by type" feature provides a better compression ratio.
These are some of the reasons why the new version of 7-Zip creates larger archives than the older version of 7-Zip.
Why aren't some ZIP archives accessible through 7-Zip?
There are two possible reasons why some RAR Archives cannot be accessed through 7-Zip.
- Archive contains incorrect headers
- Archive are encoded with the formats not supported by 7- Zip.
Why can't the command line version add files without the extension to an archive?
The 7-Zip doesn't support a ** wildcard and treats this as an extension. So prefer using * wildcard or just skip the usage of a wildcard.
What is the process to install 7-Zip in silent mode?
The Exe installer must use the "/S" parameter to install 7-Zip in silent mode. And for the MSI installer, you need to use parameters such as INSTALLDIR=C: program Files\7-Zip.
Is it possible to store the full path of a file in an archive? What is the process for that?
You can only store the relative paths of files on 7-Zip excluding the prefix of the drive letter. First, you need to change the current folder to the common folder for all the files that you want to compress, and then you can make use of a relative path as follows:
cd /D C:\dir1\
7z.exe a c:\a.7z file1.txt dir2\file2.txt
Why are temp files used to drag-and-drop archive extraction from 7-Zip to Explorer?
7-Zip doesn't have to recognize the path of the drop target folder. Only Windows Explorer can recognize the exact drop target. Windows Explorer requires files (drag source) as decompressed files on disk. Then the 7-Zip extracts files from the archive to the temp folder.
It then notifies Windows Explorer about the paths of these temp files. After that Windows Explorer copies these files to the target folder. To avoid the usage of a temp file, you can utilize the Extract command of 7-Zip or drag-and-drop from 7-Zip to 7-Zip.
Can I use the EXE or DLL files from 7-Zip in a Commercial Application?
Yes, you can use it but you will need to specify the following in your documentation:
- Specify that you used the parts of the 7-Zip program.
- Mention that the 7-Zip is licensed under the GNU and LGPL license
- You will have to provide a link to www.7-zip.org, where the source code can be found.